Anastomosis instruments of this type are known from EP 1 857 058 B1, for example. This document discloses an inclination-type anvil assembly which is suitable for being used with a circular anastomosis clip setting device. Said device comprises a center bar, a head assembly (anvil) comprising a housing, a shoulder, an anvil plate including clip deformation dents and a cutting ring supporting element. Here, the head assembly is pivotally fastened to the center bar and can be swiveled with respect to the center bar between a non-angled position perpendicular to the axis of the center bar and an angled position. The cutting ring supporting element is positioned so as to surround the shoulder and is moved along the shoulder from a first position in which a portion of the supporting element is positioned to prevent the head assembly from carrying out a swivel motion from the non-angled position to the angled position, to a second position in which the supporting element is positioned to allow a swivel motion of the head assembly with respect to the center bar from the non-swiveled position to the swiveled position, if the clip device is triggered. The head assembly further comprises a lock element which is positioned to prevent a backward motion of the supporting element from the second position to the first position, the lock element being in particular a pivoting cam lock element. Such a device is used for the preparation of a surgical end-to-end anastomosis, for instance. It goes without saying that such an instrument can also be used for side-to-side-anastomoses, side-to-end anastomoses and end-to-side anastomoses, in particular in the stomach, esophagus and bowel zones.
Regarding elaborate hand-made sutures used for connecting two parts of the bowel, for example, the instrument according to EP 1 857 058 B1 can be used as an alternative circular clip suture instrument.
With such clip suture instruments, the anvil is axially pressed against a clip magazine at the front side, with body tissue being clamped therebetween. Next, clips are stuck through the clamped tissue, for instance through the bowel, and are deformed on the anvil (or on the cutting ring supporting element), so that an axial connection between two hose-like ends of the bowel is produced. In order to restore the continuity of the hollow organ, the axial passage in the clip area is stamped out with a round blade (annular ring blade), for instance; in this process, the anvil serves as an axial counter bearing for the circular blade supported in the clip magazine.
During removal of the instrument, i.e. when the anvil is pulled (retracted/removed) through the clip suture, the connected bowel areas must not be stretched too much, as this could result in a damage of the clip suture produced immediately beforehand. This is why the anvil is tilted/pivoted by means of a spring mechanism after the clipping process in many cases. The anvil or the headpiece is supported via a headpiece shaft, a center rod or a center bar and is moved to a removal position in said case of actuation. This removal position may also be referred to as a withdrawal position. In this removal posture/position, the anastomosis instrument or the anvil (the headpiece) has a smaller projected area than in the processing position (as seen in the longitudinal direction of the instrument). The tilting operation is usually activated by the feed motion of the blade, in most cases by permanently deforming, i.e. partially destroying a retaining element such as a deformable disk.
Due to tilting the headpiece (anvil/anvil head), the circumference as seen in the direction of the longitudinal axis of the instrument is reduced by such an extent, that the set clip rows are not overstretched during the removal of the instrument. The risk of a leakage of the anastomosis is reduced due to the tiltable anvil having been transferred to the withdrawal position, as the mechanical stressing of the suture is significantly lower during removal of the instrument.
The tissue is locally perforated with the known instruments using mechanical clips as well as with a manual hand-made suture. These perforations are potential places for leakage and represent spots which are prone to inflammations. It is vital to avoid such a situation with an anastomosis instrument in the future.
The prior art, for instance the document DE 20 2010 013 151 U1, shows a surgical system which is improved in this respect and intended for connecting body tissue, comprising a surgical instrument including a connection device for connecting body tissue. Here, the connection device comprises two tool elements which can be moved relative to each other. The instrument further comprises a cutting device comprising a cutting element for the severing of tissue, the cutting element being arranged so as to be movable relative to at least one of the tool elements. The cutting element has a cutting edge defining a cutting plane which is inclined relative to a longitudinal axis defined by the instrument in the area of the connection device. This surgical system uses a high-frequency cutting device (HF cutting device) acting with electrical current. Monopolar and bipolar cutting devices are disclosed here as well.
This system allows to do without any clips, so that the so-called “Tissue Fusion Technology” (TFT) can be applied. Here, different or also identical tissue types are connected to each other by the use of HF energy, preferably in bipolar fashion. As in this technology the tissue layers are not connected to each other by clips, it is also advantageous here if only small forces act on the anastomosis/anastomosis suture during the removal of the anastomosis instrument. Here too, tiltable electrode plates are provided to avoid any damage of the anastomosis during pulling out the instrument.
Unfortunately, the instruments known from prior art for tilting the headpiece (anvil) usually are not designed to be reversible, so that a quick and easy re-employment of one and the same instrument in the context of a medical treatment or on the human body is not possible. Here, it is necessary to provide an improvement. In addition, up to now there is no possibility to determine whether the tilting operation has been carried out in a correct manner, i.e. if the headpiece has been properly transferred to the removal position.